This Laboratory Program represents the biochemistry section of a multidisciplinary effort to develop specific inhibitors against Src. This Program will be responsible for producing recombinant Src and other PTKs to (1) screen inhibitors, (2) determine the affinity of "hits" identified in the screen, (3) determine the specificity of the "hits" identified in the screen, and (4) perform structural studies of the Src active site. This laboratory program serves as a screen between the two synthetic chemistry laboratories and the two biological testing laboratories which functions to narrow down the thousands of compounds synthesized to those which are worth studying for biological efficacy. In addiction, it aids the synthetic chemistry sections in choosing which analogs to consider for synthesis and testing. The biochemistry lab has developed an infrastructure to produce recombinant PTKs and a high-through put screening of combinatorial libraries.